1. Technical Field
The present invention relates to a maintenance apparatus to maintain performance of an electronic device, and more specifically, to a maintenance apparatus that deals with time degradation of a central processing unit (CPU).
2. Background Art
Performance of an electronic device such as a computer is degraded according to degradation of a CPU that is built therein. One known cause that leads to degradation of the CPU is hot carrier effects caused by time degradation of a semiconductor device such as a transistor.
Japanese Unexamined Patent Application Publication No. 2010-203816 discloses a degradation diagnosis apparatus that detects degradation (correlative degradation) of a subject that correlatively degrades with a processing apparatus which is a target of inspection, and performs inspection of the processing apparatus when the correlative degradation is detected. This configuration aims to perform a diagnosis operation in an appropriate period.
Japanese Unexamined Patent Application Publication No. 2007-278105 discloses a system that diagnoses degradation of machines. This system measures phenomena indicating degradation (accidental fire or the like) and calculates using the measurement value as a parameter to diagnoses degradation.
Japanese Unexamined Patent Application Publication No. 2009-250959 discloses a system that monitors temporal degradation of a gas-phase adsorbing filter installed in a case or the like. This system detects the amount of a gas-phase material in the case and determines degradation of the filter based on the detection amount and information indicating a predetermined correlation.
Japanese Unexamined Patent Application Publication No. 2009-267660 discloses an image processing apparatus including a hard disk device. In this configuration, when the hard disk device is judged to be degraded more than a predetermined standard, a job is executed under a control which is different from a control employed when the hard disk device is judged not to be degraded more than the standard.
Japanese Patent No. 3857052 discloses a microprocessor that supplies, to each circuit block, a plurality of power supply voltages having different values by switching them, and a plurality of clocks having different frequencies by switching them. This configuration aims to operate a specific circuit block with high speed without increasing power consumption.
The degradation of the CPU (reduction in processing capacity) due to the hot carrier effects stated above can often be solved by increasing a power supply voltage applied to the CPU. Accordingly, it is considered that, upon detection of a failure due to the degradation of the CPU, for example, such a control is performed to increase the power supply voltage to the CPU when the electronic device is restarted, thereby being able to recover functions of the CPU (electronic device).
However, such a treatment that requires the restart operation greatly impedes a smooth use of the electronic device.
Further, according to the related arts, job management processing by a job scheduler has been executed without considering degradation of the CPU stated above. Thus, jobs are allocated to the CPU whose processing capacity is reduced due to degradation in the similar way to the case before the degradation occurs. This is considered to lead further defects on the operation of the electronic device.
The present invention aims to provide a technique of compensating time degradation of a CPU and to maintain performance of an electronic device without disturbing a normal operation of the electronic device.